How can I make an indent on a edge loop?
On a subdivided cube example you can see how a ring cut on the right side of the top face can add unnecessary faces all the way around.
Alternatively you can localise quads and save on face count in the other two cuts.
The other cut on the top face allows a flat base to the cut.
The cut on the side face of the cube creates an angled finish, adding less faces overall.